I use a Glock 34 with stream light one HLRDS holster I have the 6378 and the 6390 and I haven’t noticed any issues when using Glock 19 through 34 with a fire or stream light. Surprisingly the stream light is a little tighter than the surefire so I just do a few draws and see where it’s wearing and smooth it out with some 400 grit sandpaper no issues. The newer holsters have a new designed thumb release for the ALS and the nub mod doesn’t fit. I know the company is working on a new version just FYI.